Our long-term goals have been to identify the pathways and underlying mechanisms of synaptic transmission in the retina. We also seek to understand how synaptic pathways are regulated during development and how this development is influenced by visual inputs. Recently it has been discovered that the development of ON-OFF pathways in mouse retina requires visual stimulation. We seek to understand and characterize the role of glutamatergic synaptic transmission in guiding and promoting development of ON-OFF pathways and other synaptic pathways. A further aim is to determine how a decrease of pattern vision in young animals governs the development of synaptic pathways and visual function in retina. A final goal is to characterize how visual deprivation, produced by dark rearing, affects the development of inhibitory pathways and the functional structure of ganglion cell receptive fields. It has been commonly assumed that development of retina is not affected by visual deprivation. The profound refinements of visual function and neuronal connectivity observed in higher centers of the visual system were thought to originate in these higher regions. Now, given that visual deprivation can influence retinal function, these concepts will have to be reevaluated. These studies will be performed in mouse retina. The mouse is becoming a well-characterized and much utilized model system for development in mammals. In addition, because of the relative ease in creating transgenically engineered mice, there has been a rapid expansion in the availability of cellular markers and specific molecular deletion in these species. Even more important, however, is that the retina, being one of the best studied and well characterized areas of the visual system, affords us a chance to investigate more easily the cellular mechanisms that control development and plasticity. [unreadable] [unreadable]